A fairly quick look at it but, if we don't include any attached ships and fighters, it's pretty heavily in the Davion's favor - to the point where the Fox might escape destruction.
Including fighters pushes it to a much more even match-up - with a slight edge to the clanners, imo. In the most optimistic example I can think of, the Jaguars launch their 60 fighters well out of range of the Davions and target the Fox. This is likely to mission-kill the Fox while gutting the fighters to ineffectiveness. This leaves the combined might of the York and Congress against the Avalon. To break it down a bit further while leaving out actual specifics, this leaves a total of ~650 capital damage and 3 capital missile launchers with ~1100 armor against ~390 capital damage and 14 capital missile launchers with ~1800 armor. At this point a couple things could happen, the Avalon could maintain distance and launch capital missiles until it runs out it's ammo, or it could close with the Jaguars. Assuming the first happens, the point defense (aka, all the weapons) would probably render the Avalon's missiles mostly ineffective - I suspect somewhere between 0 and 2 would get by per salvo - this would leave the Avalon alive, but able to quit the field of battle without serious damage. In the second scenario, if the Jaguars have any sense of coordination they are likely to mission-kill the Avalon, but will suffer significant damage in response - I would expect the Congress to be mission-killed, while the York would have significant damage but still be mostly operational.
Just my take on it, there are certainly other scenarios and strategies that may give the Davions a bigger edge when fighters are involved - examples include giving both sides dropships and/or small craft.
